The present invention relates to a system for pouring concrete walls, and more particularly to tie and panel designs for use in constructing a wall form for a poured concrete wall.
Many present day poured concrete walls are constructed using prefabricated, reusable, interlocking panels. A plurality of the panels are interconnected to construct a pair of generally parallel and spaced wall forms. After the wall forms are constructed, the concrete is poured therebetween and permitted to harden or cure and the wall forms are disassembled and removed from the hardened concrete wall for subsequent reuse. The panels are necessarily of relatively high strength and are typically constructed of plywood, steel and/or aluminum and are designed to be interconnected in a side-by-side relationship.
Known panels generally include flanges which extend perpendicularly from a back face of the panel along each side edge. A series of spaced openings are provided in the flanges. When the panels are placed in juxtaposition with each other the adjacent flanges are typically interconnected by slotted pins and wedges which are separate from the panels. The slotted pins are driven through the aligned openings in the flanges and the wedge is then placed within the pin slot to lock the individual panels together. When the wall form is to be disassembled, the wedges are loosened and removed and the pins extracted from the apertures in the flanges and collected for reuse.
Use of traditional detached panel connection hardware presents a number of problems. Specifically, many of the pins and wedges are lost during the normal process of form construction and disassembly. Commonly, the pins and/or wedges fall on the ground at the construction site, in a hole, puddle or the like and simply are not or cannot retrieved by the worker. As a result, a significant number of the pins and wedges are lost which over time can be very expensive to replace.
Moreover, use of detachable hardware as described can be very labor intensive inasmuch as the panels must be held in alignment while the connection hardware is first properly positioned and then driven into place. Further, the transportation, distribution, installation and collection of the large number of pins and wedges required at a typical construction site has proven to be very time consuming and labor intensive.
In response to the problems associated with detachable and reusable panel connection hardware, attempts have been made at developing assemblies which are permanently secured to the panels. One such assembly includes a pin or a bolt which is shiftably mounted adjacent to the flange of a panel for passage through aligned flange apertures to connect the adjacent panels. Additionally, the pin includes a groove proximate the tail end thereof which is adapted to receive a locking wedge when the pin is in its retracted position to thereby maintain the pin in this position and allow for storage of the wedge.
Another attached hardware system includes a tapered pin having a rearward extension which is received within a slide block. The slide block incudes a disk designed to maintain the position of the locking pin relative to each flange aperture. The pins are driven forwardly to pass through aligned apertures of adjacent panels and a tapered wedge is used to complete the panel connection.
A number of drawbacks are associated with attached hardware systems. Specifically, such known connection systems add significant weight to the panels. A large number of panels are typically transported to a construction site and this added weight increases the transportation time and handling of the panels. Further, over time attached hardware connections become significantly misaligned or loose due to normal wear of the components. This is primarily objectionable because as a result the installer must manually align the components before panel connection can be completed.
In addition to the problems described with respect to known hardware for connecting the panels together, the current panels themselves have significant shortcomings. First of all, the panels can be quite heavy, typically weighing about 90 pounds or more each. Usually a single worker manipulates the panels and moves them around on the job site. Therefore, a lighter weight panel could not only reduce material and shipping costs, but increase labor productivity while minimizing potential injuries to the workers who handle the panels. However, lighter panels typically suffer the problem of providing insufficient strength or structural integrity to the assembled wall form. The concrete poured between the assembled panels acts substantially like a fluid and delivers significant hydrostatic pressures to the wall forms. The pressure naturally becomes greater toward the bottom of the forms. Typically, the compressive load on a concrete form eight feet high can easily reach 1,000 to 1,200 pounds per square foot. The panel, connection hardware and assembled wall form must be able to withstand these pressures without buckling, deformation or failure.
Furthermore, since the forces are not evenly distributed over the panels, the panels may shift and spread relative to one another thereby inducing significant forces on the interconnecting hardware of the panels. Further, the concrete expands as it sets creating additional forces on the wall form system and ties. In a typical concrete wall, there may be as much as 5,000 pounds of tension or pulling force or load on an individual tie which extends between the spaced wall forms.
It has therefore been a primary objective of this invention to provide tie and panel connection hardware for use with concrete wall forms which can be easily and economically used at the construction site.
It has been a further objective of this invention to provide interlocking hardware for joining the adjacent panels of a wall form together which can be easily, efficiently and economically installed and removed during assembly and disassembly of the wall forms.
It has been a further objective of this invention to provide such panel connection hardware which does not add weight to the panels but maintains a secure alignment and interconnection of the panels under the high loads applied to the wall forms.
It has been a yet further objective to provide a tie and interlocking connection for the adjacent panels which is strong enough to withstand the forces generated in the construction of a poured concrete wall.
It has also been a primary objective of this invention to provide an improved panel for use in constructing a wall form which is both lightweight and strong enough to withstand the forces generated in the construction of the poured concrete wall.